如何防止字符乱码：CharacterEncodingFilter的使用

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CharacterEncodingFilter.java

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packageblog.filter;
 
importjava.io.IOException;
 
importjavax.servlet.Filter;
importjavax.servlet.FilterChain;
importjavax.servlet.FilterConfig;
importjavax.servlet.ServletException;
importjavax.servlet.ServletRequest;
importjavax.servlet.ServletResponse;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletRequestWrapper;
 
publicclass CharacterEncodingFilterimplements Filter {
     
    privatefinal String OLD_ENCODING ="ISO-8859-1";
      
    privateString encoding = "UTF-8";
 
    publicvoid init(FilterConfig filterConfig)throws ServletException {
        String s = filterConfig.getInitParameter("encoding");
        if(s != null && !"".equals(s)) encoding = s;
    }
     
    publicvoid destroy() {
         //
    }
 
    publicvoid doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain)throws IOException, ServletException {
 
        HttpServletRequest httpreq = (HttpServletRequest) request;
         
        if(httpreq.getMethod().equals("POST")) {
            request.setCharacterEncoding(encoding);
        }else {
            request =new RequestEncodingWrapper(httpreq);
        }
 
        chain.doFilter(request, response);
    }
 
 
    privateclass RequestEncodingWrapperextends HttpServletRequestWrapper {
 
        publicRequestEncodingWrapper(HttpServletRequest request) {
            super(request);
        }
 
        publicString toChi(String input) {
            try{
                byte[] bytes = input.getBytes(OLD_ENCODING);
                returnnew String(bytes, encoding);
            }catch (Exception ex) {
            }
            returnnull;
        }
 
        /**
         * Return the HttpServletRequest holded by this object.
         */
        privateHttpServletRequest getHttpServletRequest() {
            return(HttpServletRequest) super.getRequest();
        }
 
        publicString getParameter(String name) {
            returntoChi(getHttpServletRequest().getParameter(name));
        }
 
        publicString[] getParameterValues(String name) {
            String values[] = getHttpServletRequest().getParameterValues(name);
            if(values != null) {
                for(int i = 0; i < values.length; i++) {
                    values[i] = toChi(values[i]);
                }
            }
            returnvalues;
        }
    }
 
}

 

 

 

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web.xml:

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<?xml version="1.0"encoding="UTF-8"?>
<web-app version="2.5"xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://java.sun.com/xml/ns/javaee  http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
 
 <filter>
  <filter-name>CharacterEncodingFilter</filter-name>
  <filter-class>blog.filter.CharacterEncodingFilter</filter-class>
  <init-param>
   <param-name>encoding</param-name>
   <param-value>UTF-8</param-value>
  </init-param>
 </filter>
 <filter-mapping>
  <filter-name>CharacterEncodingFilter</filter-name>
  <url-pattern>/*</url-pattern>
 </filter-mapping>
 
</web-app>